Surgical instrument having an articulated jaw structure and a detachable knife

ABSTRACT

A surgical instrument with articulated jaw structure includes a frame and two jaws. The jaws have proximal portions that are mounted to each other for movement in a substantially parallel relation between a fully open position wherein the jaws are separated for receiving tissue therebetween and an approximated position wherein the jaws are closer together. Preferably, the jaws are in the fully open position when the distal portion of at least of the jaws is located in an extended position and are in the approximated position when the distal portion of the extended jaw or jaws is located in a retracted position. The surgical instrument may further include a detachable knife assembly and knife actuating mechanism.

[0001] This invention relates generally to jaw-type surgical instrumentsand, in particular, to a jaw-type surgical instrument wherein theopposed jaws move substantially parallel over a significant part oftheir operating range and/or wherein one of the jaws includes acartridge having a knife assembly that is detachable from its operatingmechanism.

BACKGROUND OF THE INVENTION

[0002] A wide variety of surgical procedures used today involve surgicalinstrumentation having jaw structure such as grippers, graspers,dissectors, clamps, cutting elements and/or stapling elements. In eachof these types of jaw structure, selected tissue is captured by the jawsfor manipulation. One type of jaw structure currently used capturestissue by a pivotal action of the jaw structure wherein the jaws closeprogressively from a pivot point outward to the end of the jawstructure. See, for example, U.S. Pat. No. 5,040,715 to Green et al.This pivotal action, however, causes the captured tissue to be pushedaway from the jaw pivot point upon approximation, possibly resulting inuneven cutting, unintentional tissue trauma, and/or inaccurate tissuemeasurement or joining. This type of jaw structure is alsodisadvantageous in endoscopic or laparoscopic procedures wherein thesurgical instrument is inserted into the body through a cannula ortrocar because the jaws must necessarily protrude a significant distancebeyond the end of the trocar to open fully. This decreases the “maneuverroom” available to a surgeon for manipulating the device within a bodycavity.

[0003] A more accurate and atraumatic way of approximating surgical jawstructure is by parallel approximation. This approach has been describedin European Patent Application No. 92104388.1, filed Mar. 13, 1992,wherein various camming structures are described for effectingsubstantially parallel movement of first and second surgical jaws. Inone embodiment, a camming plate with diagonal camming slots is slidablymounted within a tubular frame. The camming plate is connected to amoveable jaw such that movement of the camming plate causes the moveablejaw to move into parallel approximation with a stationary jaw. Inanother embodiment, an axially slidable camming collar engages a cammingsurface on the moveable jaw to actuate the opening and closing of thejaws. Sliding the collar forward closes the jaws, whereas pulling thecollar backward opens the jaws. This design, however, creates a veryhigh frictional component to the overall opening and closing forces,affecting the overall ease of operation of the device. Additionally, inall of the embodiments described, the jaws are prevented from movingaxially, which, as will be discussed below, precludes the user fromenjoying many other advantages.

[0004] The above devices also describe jaw structures that employ astaple cartridge. Typically, the staple cartridge is provided with anaxially extending slit through which a knife passes to cut the capturedtissue at the time of stapling. An axially moveable actuating mechanism(e.g., a pusher rod) is used to push the knife through the cartridge.The location and structure of the knife actuating mechanism is wellknown for jaws having purely pivotal movement, but such is not the casefor jaws that are capable of substantially parallel approximation. Inthis latter situation, especially in connection with endoscopic orlaparoscopic procedures where accessibility is extremely limited,inclusion of the knife actuating mechanism can result in a reduction inthe maximum distance the jaws can open and/or result in furtherpenetration of the jaws beyond the end of the cannula into the bodycavity to accommodate the knife actuating mechanism.

[0005] It is also desirable to have a fresh knife available after eachtransection. In presently available apparatus, however, the knife hasbeen an integral part of the combined pusher rod/cartridge assembly.This design requires the pusher rod mechanism to be discarded after eachuse, causing waste, and requires that the overall length of thecartridge assembly be increased in size to account for the entireextended length of the pusher rod mechanism.

[0006] Another disadvantage of the above-described devices is that jawclosing is typically accomplished by actuating an axially movable rodoperably connected to the jaws. Pushing on the actuating rod closes thejaws and pulling on it opens them. Using compression force on theactuating rod, however, to close the jaws around the captured tissue canresult in buckling. This could have serious consequences if bucklingoccurred during a particularly sensitive part of the surgical procedure.

[0007] In view of the above, it should be appreciated that there isstill a need for a jaw-type surgical instrument wherein the jaws areheld substantially parallel over a significant part of their operatingrange, yet open widely with minimal extension of the jaws beyond the endof the cannula into the body cavity during the operating procedure.There is also a need for a device wherein the jaws are axially moveableto effect approximation and wherein the mechanism for closing the jawsaround the captured tissue is without risk of instrument failure due tobuckling of the push rod. Such a device would also preferably include aneasily replaceable knife without significantly affecting the operationof the jaws or requiring frequent replacement of the knife actuatingmechanism. The present invention satisfies these needs.

SUMMARY OF THE INVENTION

[0008] The present invention is embodied in a surgical instrument havingan articulated jaw structure, wherein a pair of jaws are heldsubstantially parallel over a significant part of their operating range,yet are capable of being held widely open with minimal extension of thejaws beyond the end of a mounting cannula or frame during an operatingprocedure. One or both jaws are adapted to be axially moveable relativeto the frame. The surgical instrument also includes a jaw operatingmechanism that is not subject to buckling during jaw approximation. Thepresent invention is particularly adapted for use in surgical staplinginstrumentation and permits the use of a staple cartridge/knife assemblycombination that is relatively short in length and easily replaceable.

[0009] In one embodiment of the invention, the surgical instrument witharticulated jaw structure includes a tubular frame and an actuatingmechanism moveable inside the tubular frame. The actuating mechanism hasa cam that engages corresponding camming surfaces on first and secondjaws. Each of the jaws has a proximal portion defining the cammingsurface and a distal portion. The proximal portions of the jaws arepivotally mounted to each other. The distal portions of the jaws areconfigured to capture tissue between them. The cam and camming surfacesare configured such that upon movement of the cam between a firstposition and a second position, the jaws will pivot relative to eachother between an open position and an intermediate position,respectively. One of the jaws also includes a cam stop that furtherengages the cam when the cam is in the second position such that uponfurther movement of the actuating mechanism between the second positionand a third position, the jaws will retract axially into the tubularframe. One of the jaws further includes a ramp that engages a distal endof the tubular frame upon axial retraction of the jaws. The ramp isconfigured such that the jaws move in a substantially parallel relationbetween the intermediate position and an approximated position uponmovement of the cam between the second position and the third position,respectively.

[0010] A feature of this embodiment of the invention is that the jawmotion may be broken down into two components, a primarily pivotingmotion of the jaws during initial jaw closing, which does not consumesignificant axial length between the distal portions of the jaws and thetubular frame and a substantially parallel approximating motion of thejaws that does consume axial length as the jaws are retracted into thetubular frame. Through this construction, axial stroke is substantiallylimited to the latter high force segment of the jaw closing cycle (i.e.,the compression of tissue by the approximating jaws). In turn, a shorteraxial stroke means less extension of the jaws beyond the end of thetubular frame and less protrusion into the body cavity, increasing the“maneuver room” of the surgeon manipulating the instrument.

[0011] Another feature of the present invention is that the jawmechanism may be operated by an actuating rod that closes the jaws uponpulling the rod and opens the jaws upon pushing the rod. Using tensileforce to close the jaws reduces the likelihood that the actuating rodwill buckle. Buckling can only occur during compressive loading, whichoccurs during jaw opening. Since the jaw opening force is always lowerthan the jaw closing force, the maximum buckling force is lower than itwould be if the situation were reversed.

[0012] In a second embodiment of the present invention, the surgicalinstrument with articulated jaw structure includes a frame, a fixed jawmounted to the frame at its proximal end and a moveable jaw. Themoveable jaw is connected to the fixed jaw to permit movement between anopen position wherein the distal ends of the jaws are spaced apart fromeach other and the moveable jaw is extended distally relative to thefixed jaw, and an approximated position wherein the distal ends of thejaws are closer together and the moveable jaw is substantiallyunextended relative to the fixed jaw. An actuating mechanism is providedfor moving the jaws between the open and approximated positions.

[0013] A particular feature of the second embodiment of the invention isthat the moveable jaw juts out from the fixed jaw when the jaws areopen. As the jaws close, the moveable jaw moves back along the fixedjaw, pulling tissue back toward the proximal end of the jaws. Thisinhibits tissue from extruding out of the gap between the jaws, which isopposite to the undesirable result caused by the prior art single pivotjaws wherein the tissue is pushed out of the jaws during closing.

[0014] The present invention is also embodied in a surgical instrumenthaving articulated jaw structure and a detachable knife. By including amechanism for engaging and disengaging a knife, the jaws can be heldsubstantially parallel over a significant part of their operating range,yet still open widely with minimal extension of the jaws beyond the endof their mounting cannula or frame. In addition, because the knife isdetachable, the knife may be replaced often without requiringreplacement of its actuating mechanism.

[0015] The surgical instrument with articulated jaw structure anddetachable knife of the present invention includes a first jaw and asecond jaw, one of the jaws having a longitudinal cartridge detachablymounted thereto. The first jaw and the second jaw are connected to oneanother to permit movement in a substantially parallel relation betweenan open position, which permits capture of selected tissue between thejaws and an approximated position wherein the jaws are in closeproximity to and in opposed alignment with each other. A knife assemblyis provided having a bearing surface, a knife blade defining a cuttingedge, and a latch receiver. The longitudinal cartridge slidably receivesthe knife assembly such that the cutting edge of the knife blade ispermitted to move longitudinally between the jaws when the jaws are inthe approximated position. A knife actuating mechanism having a bearingsurface and a latch is provided for moving the knife assembly from afirst position at a proximal end of the cartridge to a second positionlocated distally from the proximal end of the cartridge when the knifeactuating mechanism is moved distally. The latch is received in thelatch receiver of the knife assembly for moving the knife assembly backfrom the second position to the first position when the knife actuatingmechanism is moved proximally. A further mechanism is provided fordisengaging the latch when the knife actuating mechanism moves between alatched position and an unlatched position.

[0016] An advantage of the detachable knife is that the knife actuatingmechanism may now be a component separate from the cartridge holding theknife assembly. In stapling instrumentation, in particular, this meansthat a firing mechanism for the staples no longer needs to be anintegral part of the disposable staple cartridge. Because of this, thecartridge may be made smaller. This reduction in size is particularlybeneficial for surgical instrumentation used in endoscopic andlaparoscopic procedures.

[0017] Other features and advantages of the present invention willbecome apparent from the following description of the preferredembodiments, taken in conjunction with the accompanying drawings, whichillustrate, by way of example, the principals of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018]FIG. 1 is an exploded perspective view of a surgical instrumenthaving an articulated jaw structure made according to the presentinvention.

[0019]FIG. 2 is an assembled side view of the surgical instrument shownin FIG. 1, showing the jaws in a fully open position.

[0020]FIG. 3 is an assembled side view of the surgical instrument shownin FIG. 1, showing the jaws in an intermediate position.

[0021]FIG. 4 is an assembled side view of the surgical instrument shownin FIG. 1, showing the jaws in an approximated position, and showing aknife assembly and a knife actuating assembly made according to thepresent invention.

[0022]FIG. 5 is an enlarged side view of the knife assembly and theknife actuating assembly of the surgical instrument shown in FIG. 4.

[0023]FIG. 6 is a top sectional view of the surgical instrument shown inFIG. 4, taken along line 6-6.

[0024]FIG. 7 is a front sectional view of the surgical instrument shownin FIG. 2, taken along line 7-7.

[0025]FIG. 8 is a front sectional view of the surgical instrument shownin FIG. 2, taken along line 8-8.

[0026]FIG. 9 is a front sectional view of the surgical instrument shownin FIG. 2, taken along line 9-9.

[0027]FIG. 10 is a front sectional view of the surgical instrument shownin FIG. 3, taken along line 10-10.

[0028]FIG. 11 is a front sectional view of the surgical instrument shownin FIG. 3, taken along line 11-11.

[0029]FIG. 12 is a front sectional view of the surgical instrument shownin FIG. 4, taken along line 12-12.

[0030]FIG. 13 is a side view of a first modified surgical instrumenthaving an articulated jaw structure made according to the presentinvention showing the jaws in a fully open position.

[0031]FIG. 14 is a side view of the surgical instrument shown in FIG.13, showing the jaws in an intermediate position.

[0032]FIG. 15 is a side view of the surgical instrument shown in FIG.13, showing the jaws in an approximated position.

[0033]FIG. 16 is a side view of a second modified surgical instrumenthaving an articulated jaw structure made according to the presentinvention, showing the jaws in a fully open position.

[0034]FIG. 17 is a side view of the surgical instrument shown in FIG.16, showing the jaws in an intermediate position.

[0035]FIG. 18 is a side view of the surgical instrument shown in FIG.16, showing the jaws in an approximated position.

[0036]FIG. 19 is an enlarged side view of a portion of the surgicalinstrument shown in FIG. 18, and showing a knife assembly and a knifeactuating assembly made according to the present invention.

[0037]FIG. 20 is a partial perspective view of a third modified surgicalinstrument having an articulated jaw structure made according to thepresent invention.

[0038]FIG. 21 is a rear sectional view of the surgical instrument shownin FIG. 20 taken along line 21-21.

[0039] FIGS. 22A-H are enlarged sectional views of a knife assembly anda knife actuating assembly made according to the present invention,wherein the assemblies are shown at various stages of operation in asurgical instrument.

[0040]FIG. 23 is a top view of the knife assembly and the knifeactuating assembly shown in FIG. 22A.

[0041]FIG. 24 is a sectional view taken along line A-A in FIG. 22C.

[0042]FIG. 25 is a sectional view taken along line B-B in FIG. 22C.

[0043]FIG. 26 is an enlarged sectional view of the knife assembly.

[0044]FIG. 27 is a side sectional view of a surgical stapler, showingthe stapling and cutting of tissue between the jaws of the stapler.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0045] A preferred surgical instrument 10 with articulated jaw structureembodying the features of the present invention is shown in pertinentpart in FIGS. 1-12. Only the distal end of the instrument is shown, itbeing appreciated that the surgical instrument may be actuated usingstructure and techniques well known to those skilled in the art.

[0046] The surgical instrument 10 includes a tubular frame 12, a firstor upper jaw 16 and a second or lower jaw 18. In surgical staplingapparatus, one of the jaws (in this case, the lower jaw), may include adisposable staple cartridge 508. The tubular frame preferably includes acollar 14. Both the frame and collar are preferably made of stainlesssteel. The collar has an end portion 22 defining an opening 23therethrough for receiving the jaws. A pair of diametrically opposedarms 24 extend axially from the end portion into the interior of thetubular frame. Each arm defines an axially extending slot 26. A collarpin 28 is disposed and located by the slots 26 such that the collar pinextends transversely across the tubular frame. The arms of the collarform a relatively tight fit against the interior surface of the tubularframe. A proximal end (not shown) of the tubular frame is mounted to thesurgical instrument by methods well known to those skilled in the art.

[0047] The upper jaw 16 has a proximal portion 30 received in thetubular frame and a distal portion 32 that extends out of the endportion 22 of the collar 14. The distal portion of the upper jaw has atissue contacting surface 34. Similarly, the lower jaw 18 has a proximalportion 36 received in the tubular frame and a distal portion 38 thatextends out of the end portion 22 of the collar 14. The upper surface ofthe disposable staple cartridge 508 has a tissue contacting surface 40.

[0048] The jaws are pivotally mounted to each other such that in anapproximated position (FIG. 4), the tissue contacting surfaces are inopposed relationship to each other. The proximal portion 30 of the upperjaw 16 is a longitudinally extending bar that defines a transverseopening 42 for closely receiving the collar pin 28 located by the collar14. A proximal end 44 of the upper jaw is located by a cam 46. The camis preferably a pin that is disposed parallel to the collar pin 28,transversely across the tubular frame. The cam 46 engages a lowercamming surface 48 of the proximal end of the upper jaw. The insidesurface of the tubular frame engages an upper surface 50 of the proximalend of the upper jaw such that the tubular frame, the collar pin and thecam vertically locate the upper jaw.

[0049] The proximal portion 36 of the lower jaw 18 is a pair oflongitudinally extending members 51 that are located on each side,respectively, of the proximal portion 30 of the upper jaw (see FIGS. 6and 7). Each member 51 defines a transverse opening 52 for closelyreceiving the collar pin 28 located by collar 14. The collar pin 28provides an axis about which the lower jaw may pivot with respect to theupper jaw (see FIGS. 6 and 8). A proximal end 54 of each member 51 ofthe lower jaw defines a ramped slot 56 that receives the cam 46 (seeFIGS. 1, 6 and 9). The cam engages diagonally extending camming surfaces58 of the ramped slots. Each diagonally extending camming surfaceextends downwardly from the proximal end of the slot to the distal endof the slot (see FIG. 3). Each of the longitudinally extending members51 of the lower jaw, at distal ends 60 thereof, defines a ramp 62. Anupper portion 64 of each ramp is curved. Below each ramp is a shoulder66.

[0050] The cam 46 may be fixed to a clevis 67 that is mounted to thedistal end of an actuating rod 68. Preferably, the actuating rod isaxially moveable within the tubular frame to move the cam between first,second and third positions to be described in more detail below. Aproximal end (not shown) of the actuating rod is connected to thesurgical instrument by methods known to those skilled in the art foractuation by the operator of the instrument.

[0051] With reference now to FIGS. 2-4, the operation of the jawstructure of the surgical instrument will be described. FIG. 2 shows thejaws in a fully open position with the cam 46 in a first position A. Inthe open position, the distal portions 32, 38 of the jaws are fullyextended from the tubular member with the curved upper portion 64 of theramp of the lower jaw adjacent to the end portion 22 of the collar 14.The collar pin 28 is in a first position at a distal end 72 of thecollar arm slots 26. The cam 46 is between the lower camming surface 48of the upper jaw and a lower end 76 of the ramped slot 56, preventingcounterclockwise rotation of the lower jaw about the collar pin 28.

[0052]FIG. 3 shows the jaws in an intermediate spaced position (see alsoFIG. 11). By pulling on the actuating rod 68, the cam 46 is axiallyretracted from the first position A at the lower end 76 of the rampedslot to a second position B at an upper end 78 of the ramped slot.During the axial retraction, the cam 46 engages the diagonally extendingcamming surface 58 of the ramped slot to cause the lower jaw to pivot ina clockwise direction about the collar pin 28 with respect to the upperjaw. Jaw motion takes place rapidly relative to the axial movement ofthe actuating rod. Preferably, movement of the jaws from the fully openposition to the intermediate position is accomplished with little or noaxial movement of the jaws relative to the tubular member. A highclamping force between the jaws is unnecessary at this stage of theoperation because the jaws are only beginning to capture tissue betweentheir tissue contacting surfaces. Notably, in the intermediate position,the collar pin 28 is still located near the distal end 72 of the collararm slots 26 and the cam 46 still engages the lower camming surface 48of the upper jaw. Further, the lower jaw has moved into a positionwherein further axial movement of the lower jaw will cause the curvedupper portion 64 of the ramp 62 to contact a lower edge 70 of theopening 23 of the collar (see also FIGS. 1 and 10). It is theinteraction between the ramp and the collar that will cause the jaws toapproximate in a substantially parallel relation.

[0053]FIG. 4 shows the jaws in an approximated position wherein the cam46 has been pulled from the second position B to a third position C.During the axial retraction, the cam 46 engages the upper end of theramped slot 56 which acts as a cam stop 80, forcing the lower jaw and,correspondingly, the upper jaw (through the connection at the collar pin28) to retract axially into the tubular frame. Axial retraction alsocauses the jaws to approximate due to engagement of the ramp 62 with thelower edge 70 of the opening of the collar (see also FIG. 12).

[0054] During the approximating phase of operation, jaw movement takesplace slowly in relation to actuating rod movement. High clamping forcesare desired at this point due to the high force required to compress thetissue captured between the jaws. High force multiplication occurs asthe ramp 62 bears against the lower edge of the opening of the collar14. Notably, in the approximated position, the collar pin 28 has movedto a proximal end 82 of the collar arm slots 26 and the jaws are fullyretracted into the collar, with the collar contacting the shoulder 66 onthe lower jaw adjacent the lower end of the ramp 62.

[0055] It will be appreciated that the above described constructionenables the jaws of the instrument to open widely with relatively littleextension of the jaws beyond the end portion 22 of the collar 14 (asshown by the vertically oriented dashed line L at the left end of FIGS.2-4). This result is achieved by dividing the jaw closure action intotwo parts: a first part, wherein the actuating rod moves the cam fromposition A to position B, which requires very little, if any, axialmovement of the jaws and, a second part, wherein the actuating rod movesthe cam from position B to position C, which does require axial movementof the jaws. Notably, the second part of the jaw closure action islimited to the segment where high forces are required to compress thecaptured tissue between the jaws. It will also be appreciated that thejaws are held substantially parallel over a significant portion of theiroperating range, and, in particular, between their intermediate andapproximated positions.

[0056] In the preferred embodiment, the ramped slots 56 of the lower jawhave a triangular or a quadrilateral shape. This permits the lower jawto move vertically or to rotate relative to the cam 46, withoutrequiring actuation of the actuating rod by the operator.

[0057] With reference now to FIGS. 13-15, a first modified embodiment100 of the surgical instrument is shown having a tubular frame 102, anactuating rod 104, an upper jaw 106 and a lower jaw 108. In thisembodiment, the collar has been omitted and an elongated clevis 112 hasbeen fixed to the distal end of the actuating rod 104. The clevis has adistal portion 114 and a proximal portion 116. The distal portion 114defines an axially extending slot 118 for locating a clevis pin 128 suchthat the clevis pin extends transversely across the tubular frame 102. Acam 110, in the form of a pin, is fixably mounted to the proximalportion 116 of the clevis such that it is disposed parallel to theclevis pin 128 and transversely across the tubular frame.

[0058] The upper jaw 106 has a proximal portion 130 received in thetubular frame 102 and a distal portion 132 that extends out of a distalend 120 of the tubular frame. The distal portion of the upper jaw has atissue contacting surface 134. Similarly, the lower jaw 108 has aproximal portion 136 received in the tubular frame and a distal portion138 that extends out from the distal end of the tubular frame. Thedistal portion of the lower jaw has a tissue contacting surface 140.

[0059] The jaws are pivotally mounted to each other such that in anapproximated position (FIG. 15), the tissue contacting surfaces are inopposed relationship to each other. The proximal portion 130 of theupper jaw 106 is a longitudinally extending bar that defines a traverseopening 142 for closely receiving the clevis pin 128. A proximal end 144of the upper jaw defines an axially extending slot 146 that receives thecam 110. The slot 146 is horizontally disposed in FIGS. 13-15.

[0060] The proximal portion 136 of the lower jaw 108 is a pair oflongitudinally extending members 151 that are located on each side,respectively, of the proximal portion 130 of the upper jaw. Eachlongitudinally extending member 151 defines a transverse opening 152 forclosely receiving the clevis pin 128. The clevis pin 128 provides anaxis about which the lower jaw may pivot with respect to the upper jaw.A proximal end 154 of each member 151 of the lower jaw defines a rampedslot 156 that receives the cam 110. The cam engages camming surfaces 158of the ramp slots. In FIG. 13, the camming surface extends downwardlyfrom the proximal end of the slot to the distal end of the slot. Each ofthe members 151 of the lower jaw also defines a ramp 162 at a distal end160 thereof. An upper portion 164 of each ramp is curved. Below eachramp is a shoulder 166.

[0061]FIG. 13 shows the jaws in a fully open position with the cam 110in a first position A and the distal portions 132, 138 of the jaws fullyextended from end 120 of the tubular frame 102. The cam 110 is at adistal end 122 of the upper jaw slot 146 and at a distal end 124 of theramped slot of the lower law 156, preventing counterclockwise rotationof the lower jaw about the clevis pin 128. The clevis pin 128 is in afirst position at a proximal end 126 of the clevis slot 118. Uppersurfaces on the proximal portions of both jaws may be configured tocontact the interior surface of the tubular frame.

[0062]FIG. 14 shows the jaws in an intermediate spaced position whereinthe cam 110 has been pulled from the first position A at the distal end124 of the ramped slot 156 of the lower jaw to a second position B at aproximal end 131 of the ramped slot. During the axially retraction, thecam 110 engages the camming surface 158 of the ramped slot to cause thelower jaw to pivot about the clevis pin 128 in a clockwise directionwith respect to the upper jaw. Notably, in the intermediate position,the clevis pin 128 is now located at a distal end 127 of the clevis slot118 and the cam 110 is located at a proximal end 133 of the upper jawslot 146, it being appreciated that the upper and lower jaw slots arenow horizontally aligned.

[0063]FIG. 15 shows the jaws in an approximated position wherein the cam110 has been pulled from the second position B to the third position C.During the axial retraction, the cam engages both slot ends of the upperand lower jaw slots, the slot ends acting as a cam stop 168, forcing thejaws to retract axially into the tubular frame. Axial retraction furthercauses the jaws to approximate due to engagement of the ramp 162 withthe end 120 of the tubular frame. The lower jaw may also be permitted torotate about the cam 110 during retraction. Notably, in the approximatedposition, the clevis pin 128 is still located at the distal end 127 ofthe clevis slot 118. It will be appreciated that the operation andbenefits of the present embodiment are generally similar to that of thepreviously described embodiment.

[0064] With reference now to FIGS. 16-18, a second modified embodiment200 of the present invention is shown wherein only one of the jaws isaxially movable. The surgical instrument includes a frame member 212, anupper jaw 216 and a U-shaped lower jaw 218. The upper jaw has a proximalportion 230 fixably mounted to the frame member and a distal portion 232having a tissue contacting surface 234. The lower jaw 218 has a proximalportion 236 mounted to the upper jaw and a distal portion 238 having atissue contacting surface 240. The jaws are pivotally mounted to eachother such that in an approximated position (FIG. 18), the tissuecontacting surfaces of the jaws are in opposed relationship to eachother.

[0065] The proximal portion 230 of the upper jaw includes anarticulating mechanism for opening and closing the jaws. In particular,the proximal portion defines three pins arranged parallel to each otherand which protrude transversely from each side of the upper jaw, a firstpin 220, a cam pin 222 and a pivot pin 224. A link 228 is pivotallymounted to the pivot pin 224 on each side of the upper jaw. As the linkon each side of the jaw is identical, only one will be described. Adistal end 242 of the link is provided with a link pin 226 that isparallel to the other pins and extends outwardly from the link. It willbe appreciated that there is a space between the links for receiving aknife actuating assembly, as more fully described in connection withFIG. 19.

[0066] The proximal portion 236 of the lower jaw has an articulatingmechanism that corresponds to the articulating mechanism of the upperjaw. In the preferred embodiment, both upstanding walls of the U-shapedlower jaw have identical corresponding articulating structure at theproximal portions, namely, a first slot 244 for receiving the first pin220 of the upper jaw and a second slot 246 for receiving the link pin226 located at the distal end of the link 228. The first slot 244extends diagonally downward from a proximal end 248 to a distal end 250.The second slot 246 has two portions, a proximal portion 252 having amild slope relative to the longitudinal axis of the lower jaw and adistal portion 254 having a steep slope that is preferably disposed atan angle greater than 90° relative to the longitudinal axis of the lowerjaw. The proximal portion of the lower jaw further includes a camsurface 256 for engaging the cam pin 222 of the upper jaw. The camsurface extends diagonally upward towards the proximal end of the lowerjaw.

[0067] The distal ends of the links 228 may be mounted to a clevis 266of an actuating rod 268 which is axially movable. Preferably, the clevisis pivotally mounted to the actuating rod about a traverse axis parallelto the pins 220, 222, 224, 226. A proximal end (not shown) of theactuating rod is connected to the surgical instrument by methods knownto those skilled in the art for actuation by the operator of theinstrument. The link pin 226 is movable between first, second and thirdpositions to be described below in more detail.

[0068] The operation of the jaw structure of the second modifiedembodiment will now be described. FIG. 16 shows the jaws in a fully openposition with the link pin 226 in a first position A and the. lower jawextended distally relative to the upper jaw. The first pin 220 is in afirst position at the proximal end 248 of the first slot 244 whereas thelink pin 226 is at an upper end 260 of the distal portion 254 of thesecond slot. The cam pin 222 is at an upper end 270 of the cam surface256.

[0069]FIG. 17 shows the jaws in an intermediate spaced position whereinthe link pin 226 has been pulled by the actuating rod from the firstposition A to a second position B. During the axial retraction, the link228 rotates in a counterclockwise direction causing the link pin 226 toride down the distal portion 254 of the second slot, pulling the lowerjaw proximally. It is this axial linear motion of the lower jaw thatpulls tissue into the gap between the jaws and inhibits tissue fromextruding out of the gap during approximation. In addition to the axialmotion, the lower jaw also draws closer to the upper jaw due to itsrotation about the link pin 226 as the first pin 220 slides from a firstposition at the proximal end 248 of the first slot to a second positionnear the distal end 250 of the first slot. Jaw motion from the openposition to the intermediate position, takes place rapidly relative toactuating rod movement. A high clamping force is unnecessary at thisstage of the operation because the jaws are only beginning to capturetissue. Notably, in the intermediate position, the cam pin 222 is at alower end 272 of the cam surface 256.

[0070]FIG. 18 shows the jaws in an approximated position wherein thelink pin 226 has been pulled by the actuating rod from the secondposition B to a third position C. During the axial retraction, the linkpin 226 rides up the proximal portion 252 of the second slot, causingthe lower jaw to close further as it rotates about the first pin 220.During this phase of the operation, jaw motion takes place slowly inrelation to actuating rod movement. High clamping force is desired dueto the high force required to compress the captured tissue between thejaws. Notably, in the approximated position, the first pin 220 moves tothe distal end 250 of the first slot and the cam pin 222 remains at thelower end 272 of the cam surface 256.

[0071] It will be appreciated that the cam pin 222 is particularlyuseful for reopening the jaw structure. In moving from the approximatedposition to the intermediate position, the cam pin 222 will engage thecam surface 256 to urge the lower jaw to its fully open, extendedposition. On the other hand, a biasing mechanism, such as a spring 274,may be connected between the proximal portion 236 of the lower jaw andthe frame 212 to urge the lower jaw from its fully open position to theintermediate position (see FIG. 16).

[0072] As with the previously described embodiments, the second modifiedembodiment enables the jaws of the instrument to open widely withrelatively little extension of the jaws beyond the end of the frame.Furthermore, the jaws are held substantially parallel over a significantportion of their opening range and, in particular, between theirintermediate and approximated positions.

[0073] With reference to FIGS. 20 and 21, a third modified embodiment300 of the present invention is shown. As with the second modifiedembodiment, an upper jaw 310 has a proximal portion 312 that includes anarticulating mechanism for operating the jaws. The proximal portionincludes a collar 314 defining a longitudinally extending opening 316 atthe center thereof. A first pin 320 is mounted to the collartransversely across the longitudinally extending opening 316. A cam pin322, parallel to the first pin 320, extends outwardly from each side ofthe collar. A pivot pin 324, parallel to the first pin and the cam pin,extends outwardly from each side of the proximal portion of the upperjaw, adjacent the collar. A link 328 is pivotally mounted to each sideof the upper jaw at the pivot pin 324. A distal end 329 of each link isprovided with a link pin 326 that is parallel to the other pins andextends outwardly from its respective link.

[0074] A U-shaped lower jaw 330 includes a base wall 332 and twoupwardly extending side walls 334. In addition, the lower jaw isprovided with an interior cam plate 336 that is disposed in thelongitudinally extending opening 316 of the upper jaw. A mounting blockor blocks 350 may be used to mount the cam plate 336 to the upwardlyextending side wall(s) of the lower jaw. The mounting blocks may beplaced between the sides of the cam plate and each of the upwardlyextending walls, just below the lower surface of the upper jaw. As inthe second modified embodiment, a first slot 338 is provided forengaging the first pin 320, a second slot 340 is provided for engagingthe link pin 326 and a cam surface 342 is provided for engaging the campin 322. In this instance, however, the first slot 338 is disposed inthe interior cam plate 336 of the lower jaw, not in the upwardlyextending walls. In this regard, it will appreciated that the operationof the jaws of the third embodiment, between the fully opened, theintermediate and the approximated positions is similar to that fullydescribed in connection with the second modified embodiment and need notbe further described.

[0075] With reference now to FIGS. 1 and 4, the surgical instrument, inthis case, a surgical stapling apparatus, is shown having a knifeassembly 510 mounted in the disposable staple cartridge 508 forlongitudinally slidable movement therein. The construction of the staplecartridge and the techniques for operating the stapling mechanism arewell known to those skilled in the art. Briefly, however, the staplecartridge is typically a longitudinally extending member that isdetachably mounted within the U-shaped lower jaw 18 of the surgicalinstrument. The staple cartridge includes a longitudinal slit 514 and anumber of slots 516 arranged on both sides of the slit and adapted toaccommodate staples 518 and staple pushers 520 (see also FIG. 27). Theupper jaw or anvil jaw 16 of the surgical stapler typically includes alongitudinal slit (not shown) aligned with the slit 514 of the staplecartridge when the jaws are in the approximated position and alsoincludes a plurality of rows of depressions 523 aligned with the stapleslots 516 for bending the staples fired from the staple cartridge. Toeject the staples, a plurality of pusher rods 524, pointed at theirdistal ends 526 are inserted through additional slits 528 in theproximal end of the staple cartridge (see FIGS. 23 and 24) to slidelongitudinally therein. The pusher rods contact the pushers 520, causingthe pushers to rise and expelling the staples 518 out of their slots(FIG. 27). Tissue 529 captured between the jaws is thus stapled and cut.

[0076] With reference now to FIGS. 22A-H, the knife assembly 510 isshown mounted in the staple cartridge. The knife assembly includes alongitudinally extending knife support 530 having a proximal end 532 anda distal end 534 and a knife blade 536 defining a cutting edge 538. Theknife blade extends upwardly from the support with its cutting edgefacing distally. With reference to FIG. 26, the knife blade includes anintegral base 540 that may be seated in a notched area 542 at the bottomof the knife support with the cutting edge of the blade protrudingthrough an opening 544 at the top of the knife support.

[0077] The proximal end 532 of the knife support includes a pair oflatch receivers 546 extending transversely from each side of the knifesupport. Each latch receiver may be configured as a trapezoid having aproximally located, upwardly extending, ramp 548 and a distally located,downwardly extending, ramp 550.

[0078] The knife assembly is received in a longitudinally extendingopening of the staple cartridge, with the knife blade extending upwardlythrough the longitudinal slit 514 of the staple cartridge. The knifeblade is initially disposed in a protective shield 551 at the proximalend of the staple cartridge. The bottom of the staple cartridge includesa recessed portion 553 and a trough portion 554 for receiving the knifesupport 530 of the knife assembly (See FIG. 24). The recessed portion553 closely receives the knife support, whereas the trough portion 554defines a tunnel 552 on each side of the knife support, the purpose ofwhich will be described in more detail below in connection with theoperation of the knife actuating assembly. The additional slits 528shown in FIG. 24 are for receiving the pusher rods 524 previouslydescribed.

[0079] A knife actuating assembly 512 for moving the knife is also shownin FIGS. 22A-H. The knife actuating assembly includes a base 556, ablade support 558 and two latch assemblies 560. The blade support ispreferably a metal blade that is fixedly centered on the top of the baseand disposed in a longitudinal direction. The latch assemblies eachinclude a flexible latch arm 562 having a proximal end 564 and a distalend 566. A latch 568 is disposed at the distal end of each latch arm.The proximal ends of the latch arms are fixedly mounted within a recess570 at the bottom of the base. The recess includes a beveled portion 572at the distal end of the base to permit the latch arms to deflectupwardly. The proximal end (not shown) of the knife actuating assemblyis connected to the surgical instrument by methods known to thoseskilled in the art for actuation by the operator of the instrument. Theknife actuating assembly is movable between a first latched position, asecond latched and an unlatched position, as will be described in moredetail below.

[0080] Preferably, the pusher rods 524 are also mounted to the knifeactuating assembly to ensure that the pusher rods and the knife blade536 move simultaneously in a predetermined manner through the staplecartridge during the stapling/cutting procedure. With reference to FIGS.4 and 5, the knife assembly 510 and the knife actuating assembly 512 areshown located in the first embodiment of the invention. The staplecartridge and knife assembly 510 form an integral disposable part thatis located in the distal portion of the lower jaw (see FIG. 1). Theknife actuating assembly is located in the tubular frame 12 between thelongitudinally extending members 51 of the lower jaw. The blade support558 and pusher rods 524 are located below the proximal portion 30 of theupper jaw. Alternatively, the proximal portion of the upper jaw may beconfigured to permit free movement of the blade support and pusher rodslongitudinally through the tubular frame. Notably, when the jaws are inthe fully open and intermediate positions, the knife assembly typicallycannot be operated because it is out of alignment with the knifeactuating assembly. In the approximated position (FIGS. 4 and 5), theknife assembly and knife actuating assembly are aligned. In thisposition, the staple cartridge is ready to be fired and the knife isready to be actuated to cut through tissue captured between the jaws.

[0081] With reference to FIG. 19, the second modified embodiment issimilarly shown having the knife assembly 510 and knife actuatingassembly 512 located in the surgical instrument. The knife assembly islocated in the distal portion 238 of the lower jaw and the knifeactuating assembly is located at the bottom of the proximal portion 236of the lower jaw between the links 228. The blade support 558 and pusherrods 524 are located below the proximal portion 230 of the upper jaw. Aswith the first embodiment shown in FIG. 5, the knife assembly typicallycannot be operated when the jaws are in the open and intermediatepositions (FIGS. 16 and 17), but is operable in the approximatedposition (FIG. 18).

[0082] With reference now to FIG. 23, the knife actuating assembly 512is shown initially engaged to the knife assembly 510 and staplecartridge 508. In particular, the pusher rods 524 are located by theslits 528, which have beveled outer edges 574 to facilitate entry. Theblade support 558 is located by a shallow slit 576 formed into the uppersurface of the knife support 530 (See also FIGS. 24 and 26). The shallowslit may also be beveled to facility entry of the blade support.

[0083] With reference now to FIGS. 22A-22H the operation of the knifeactuating assembly will be described. FIG. 22A shows the knife actuatingassembly in an unlatched position wherein the latch 568 and the bladesupport 558 are out of contact with the staple cartridge 508 and knifeassembly 510. FIG. 22B shows a prelatched position, with the knifeactuating assembly moved from right to left as shown by the arrow. Theblade support 558 is located in the shallow slit 576 at the top of theknife support 530 and the latch receiver 546 has deflected the latch 568upwardly as the latch rides up the ramp 548. Notably, the knife assemblyhas not moved forward yet, despite the horizontal component of forceapplied by the latch to the latch receiver, because a detent 578integral with the bottom of the cartridge offers adequate resistance toforward motion at this point. FIG. 22C shows a first latched position atthe proximal end of the cartridge, wherein the latch has dropped behindthe latch receiver (see also FIG. 25 showing the latch arms 562 disposedover the latch receivers 546).

[0084]FIG. 22D shows the knife actuating assembly in a firing position,wherein a bearing surface 580 of the base 556 contacts a bearing surface582 at the proximal end 532 of the knife assembly and starts pushing theknife assembly forward, overcoming the resistance of the detent.Notably, the blade support 558 does not quite contact the back surfaceof the knife blade 536, its purpose being to act as a support in casethe resistance to cutting is so great that the knife assembly tends totilt backwards. It should also be appreciated, that the latches 568 ofthe knife actuating assembly are engaged in the tunnels 552 located oneach side of the knife support 530 of the knife assembly, at the bottomof the cartridge (see FIG. 24). The location of the latches in thetunnels becomes important when it is time to withdraw the knife, becausea roof 584 of each tunnel will ensure that the latches cannot disengagefrom the latch receivers until the knife is fully retracted.

[0085]FIG. 22E shows the knife assembly in a second latched positionwherein the knife actuating assembly withdraws the knife assembly fromleft to right as shown by the arrow. In this position, the latch 568engages the distally located ramp 550 of the latch receiver 546. Theroof 584 of the tunnel 552 prevents removal of the latch, thus the latchis able to pull the knife assembly through the longitudinal slit. FIG.22F shows a stopped position wherein the knife actuating assembly haspulled the knife assembly back as far as it will go. A rib 586, formedas an integral part of the cartridge, does not allow the knife blade 536to retract any further. FIG. 22G is a disengaged position wherein thelatch receiver 546 has deflected the latch 568 upwardly as the latchrides up the distally located ramp 550. Notably, the proximal end 532 ofthe knife support 530 has emerged from the tunnels 552 at this point(see also FIG. 23) and the latch 568 is free to deflect upwardly. Sincethe knife assembly is held in position by the rib 586, the knifeactuating assembly continues to move backwards (left to right) anddisengages from the knife assembly which remains in the cartridge, asshown in FIG. 22H.

[0086] It will be appreciated from the foregoing description that thepresent invention describes a knife assembly that is an integral part ofthe disposable staple cartridge and also describes a reusable knifeactuating assembly which stays with the reusable instrument. The knifeactuating assembly includes a latch that is captured by a latch receiverin the knife assembly. As the knife actuating assembly moves forward, itbears against with the knife assembly and moves the knife forward to cutthe tissue captured between the jaws. The knife assembly stays engagedto the knife actuating assembly as the latter is retracted until theknife assembly reaches its starting position, at which point the twoassemblies unlatch and the knife actuating assembly is free to befurther retracted out of the disposable staple cartridge.

[0087] The present invention eliminates the need for a rigid connectionbetween the knife and its actuating mechanism. This permits thecartridge jaw to be articulated near the point where the knife connectswith its actuating mechanism. Articulation at this location frees thejaw from simply rotating about a single pivot point and offers anopportunity to implement near-parallel jaw closure. The invention isparticularly suitable in endoscopic or laparoscopic procedures whereinit is desired that the jaws open widely in an essentially parallelrelationship while at the same time extending minimally beyond the endof the tubular frame of the surgical instrument.

[0088] Optionally, any of the devices described herein may include ablocking body as described in copending U.S. Patent Application No.______, attorney reference no.: 49658USA4A, entitled, “LaparoscopicSurgical Instrument With a Mechanism For Preventing Its Entry Into theAbdominal Cavity Once It Is Depleted and Removed From the AbdominalCavity”, filed in the name of inventors Claude A. Vidal, Alan K. Plyleyand Russel J. Redmond on Apr. 30, 1993. The entire contents of thatapplication are herein expressly incorporated by reference.

[0089] It will, of course, be understood that modifications to thepresently preferred embodiment will be apparent to those skilled in theart. Consequently, the scope of the present invention should not belimited by the particular embodiments discussed above, but should bedefined only by the claims set forth below and equivalents thereof.

1-40. (Canceled)
 41. A surgical instrument with articulated jawstructure for capturing tissue of a body, comprising: a frame; a fixedjaw having a proximal portion and a distal portion, the proximal portionbeing rigidly mounted to the frame; a movable jaw having a proximalportion and a distal portion; means for connecting the jaws to permitthe movable jaw to move between an open position wherein the distalportions of the jaws are spaced apart from each other and the movablejaw is extended distally relative to the fixed jaw and an approximatedposition wherein the distal portions of the jaws are closer together andthe movable jaw is substantially unextended relative to the fixed jaw;and an actuating mechanism for operating the connecting means.
 42. Thesurgical instrument of claim 1, wherein the connection means includes alinkage having a proximal end pivotally mounted about a transverse axisto one of said jaws and a distal end, a first cam on the distal end ofsaid linkage, a second cam associated with the one of said jaws, firstand second camming surfaces associated with the other of said jaws forengaging said first and second cams, and said cams and camming surfacesconfigured to permit movement of the jaws between the open position andthe approximated position upon movement of the distal end of thelinkage.